146 Prof. Buff on the Electrical Properties of Flame. 



wooden floor touched the ends of the wire which formed the 

 helix of the instrument with different metals, a deflection of 

 several degrees was obtained. The two cells before mentioned, 

 when connected by the floor, caused a deflection of 25°. The 

 wooden floor was thus proved to be an incomparably better con- 

 ductor than air heated to 40CT. 



When the strips of platinum were exposed to the direct action 

 of the flame of a spirit-lamp, the first notice of the passage of 

 electricity was obtained when they were placed at about three 

 inches above its extreme point, and began to show signs of red- 

 ness. The deflection increased as the strips were lowered into 

 the flame, and attained its maximum at a small distance beneath 

 the point of the cone into which the flame shaped itself. When 

 the flame was strongest, there was a permanent deflection of 75°. 



In these experiments care was taken to preserve the strips of 

 platinum as nearly as possible at the same temperature. The 

 two cells were removed, and the electricity of the flame itself was 

 exhibited when the two strips were placed, the one above the 

 other, within the flame, with their flat surfaces horizontal, so 

 that they assumed different temperatures. The flame-current 

 passed always from the hottest platinum strip through the sepa- 

 rating interval of gas to the other strip. 



Another attempt was made to ascertain the point at which 

 heated gas permitted the passage of electricity. In the centre 

 of the flame from a Berzelius's lamp is a cone-shaped obscure 

 mass of air as yet unburned, but strongly heated by its vicinity 

 to the flame ; into this two platinum wires connected with the 

 two cells were introduced from beneath ; they were not heated 

 to redness, but the gas nevertheless possessed a weak capacity of 

 conduction. An approximation to the blue rim of the flame 

 showed an increase of conductive power, and a deflection of 

 several degrees was obtained. 



When in this case one of the wires was caused to approach 

 the blue edge of the flame, while the other remained at a distance, 

 a deflection of 1° to 2° was obtained after the removal of the 

 two cells ; the deflection indicated the passage of a current from 

 the hotter to the cooler wire. 



The aperture, through which the air passed upwards into the 

 flame was stopped, and thus the dark interior of the flame be- 

 came formed of the vapour of alcohol and the products of its 

 decomposition; two isolated platinum wires were introduced 

 through the stopping-cork into the central space, but as long as 

 they were kept at some lines distant from the inflamed portion 

 no trace of electricity passed from one to the other. When they 

 were caused to approach the burning portion, the described phse- 

 nomena exhibited themselves. In this case also a current was 



